Dental apparatus



Jam 116;"11923.. MMA@ M. F. BURNS. DENTAL APPARATUS. FILED JUNE 3, 1922.

/IIIllI/IIIIII 4 .Will/11111 ZZ/ nvm/roe Patented ulan., i6, 1923.,

:MARTIN F. BURNS, OIF ASTORIA, NEW YORK.

DENTAL APPARATUS.

Application led .Tune 3, 1922.

To all w wm t may concern Ee it known that I, MARTIN F. BURNS, a citizen of the United States, and a resident of Astoria, county of Queens, and State of New York, have invented certain new and useful Improvements in Dental Apparatus, of which the following is a specification.

This invention relates to dental apparatus and more particularly to dental ilaslrs and to investment holders used in casting,- plates, bridges7 inlays and other restorations.

In casting a plate, bridge or other restoration a dentist first makes a pattern in wax of the article to be cast. The pattern is then placed in an investment holder and is invested in an initially plastic and quick hardening composition. `When the investment is dry or has set the wax is melted out or otherwise dissipated and the cavity is filled with molten metal. rEhe metal is forced into the cavity under pressure to effect the complete filling of the cavity. The casting is then allowed to cool and is preferably cooled slowly to prevent warpingr or distortion.

During the process of making` a cast-ing in the manner just described the investment holder is placed under considerable strain due to the heat and to the pressure and it has been found that warping or distortion of investment holders sometimes takes place.

@ne of the objects of the invention is to provide an investment holder so constructed and arranged that the holder will not be warped or distorted.

Another object of the invention is to provide an investment holder so .constructed that the holder can be used without the necessity of using a receptacle or other container.

Another object of the invention is to provide an investment holder so constructed as to facilitate the removal of the invest-ment after the castinghas been made.

Further objects of the invention will. appear from the following description taken in connection with the drawings which form a part of the application and in which- Fig. l is a view, partly in elevation and partly in section, showing dental apparatus constructed in accordance with the invention.

Serial No. 565,718.

2 is a perspective view of one form or investment holder constructed 1n accordance with the invention.

Fig'. 3 is a sectional elevation taken substantially on line S of Fig. l.

lira'. l is a sectional elevation of another investment holder constructed in accordance with the invention.

Fig. 5 is an end elevation of the holder shown in Fig. l, and

Fig. 6 illustrates in section another form of investment holder constructed in accordance with the invention.

rlfie invention briefly described consists of an investment holder comprisingl a pair of spaced preferably substantially parallel plates, connecting` means between the plates and laterally extending reinforcing` ribs secured to or formed integral with the spaced plates. ln the forms of the invention illustrated these ribs extend longitudinally of the plates and si'lbstantially throughout their length. lu order to adapt the holder for use without employing a receptacle or container the invcsi'inient holder has formed thereon at its upper end an annular flange or collar extending longitudinally of the holder. In order to facilitate the reinovalof the investment after the casting has been made one form of the holder is shown as having` openings in the plate connecting portions, these openings at the opposite sides being;` disposed at opposite ends of the holder. Further details of the invention will appear as the description proceeds.

The investment holder comprises a pair of spaced7 longitudinally extending` sub* stantially parallel preferably flat plates 10 and 1l. ln the form of the vinvention shown in Figs. 1 3 inclusive these plates are connected substantially throughout their leiwth by curved walls l2. Each of the plates nas formed thereon at its upper end a laterallj" extending;` flange the outer edges of the flanges being curved and being disposed in the same cylinder surface as the outer surfaces of the curved connecting walls l2.

In order to strengthen the holder and to prevent distortion or iwarpingeach plate has preferably formed integrally therewith a laterally extending rib 'let and in the forms of the invention shown these ribs extend longitudinally of the plates and substantially throughout their length.

It is sometimes desirable to use the investment holder without an outer container or receptacle and in order to render such use practical the holder shown in the drawings has formed thereon an upwardly extending annular flange or collar 15. rllhis collar is so constructed that its outer surface is disposed in the cylindrical surface above described and encompassing the outer edges of the flanges 13 and the curved outer surfaces of the walls 12. When the investment holder is used without a receptacle or container the collar or flange 15 prevents the investment from overflowing the holder. To further facilitate the use of the holder shown in Fig. 2 without a receptacle a collar or ring 15 may be used and this ring is so constructed as to conform in curvature tothe curvature of the ends 12 of the holder. The purpose of the ring is to properly position the holder in the casting machine, the ring being adapted to fit into the machine in the place of the receptacle or container which is not used.

The holder may of course be used in connection with the usual receptacle or container and such use is illustrated in Fig. 1 wherein the receptacle is shown at 16 the cover plate at 17 and bottom plate at 18. A cap 19 is also shown as sealing the cover plate.

In the form of the invention illustrated in Fig. 4 a plurality of reinforcing ribs 20, 21 and 22 is shown, the ribs extending longitudinally and being formed integral with the plates 10 and 11.

In Fig. 6 a plurality of radially extending ribs 30, 31 and 32 is shown.

In Figs. 4 and 5 the end walls connecting the plates are shown as provided with openings 24 and 25, the opening at 24 being adjacent the upper end of the wall and the opening 25 being shown as adjacentthe lower end of the wall. These openings are provided for the purpose of permitting the insertion of a suitable tool for removing the investment after the casting has been made.

From the foregoing description it will be seen that a simple, practical and eflicient construction of investment holder has been designed. The reinforcing ribs effectively prevent warping or distortion and the longitudinally extending flange or collar 15 permits the use of the holder without using a receptacle or container. In the form of the invention shown in Figs. 4 and 5 the openings 24 and 25 facilitate the removal of the investment.

Although certain specific embodiments of the invention have been illustrated and described, it will be understood that the invention is capable of further modification,

and that further changes in the construction and in the arrangement of the various cooperating parts may be made without departing from the spirit or scope of the invention as expressed in the following claims.

l/Vhat I claim is 1. An investment holder comprising a pair of fiat spacedplates and reinforcing ribs extending longitudinally of said plates.

2. An investment holder comprising a pair of flat spaced plates and reinforcing ribs extending longitudinally of said plates substantially throughout their length.

3. An investment holder comprising a pair of flat spaced plates and reinforcing ribs extending longitudinally of said plates and substantially at right angles thereto.

4. An investment holder comprising a pair of flat spacedplates, each plate having a reinforcing rib extending substantially throughout its length.

5. An investment holder comprising a pair of flat spaced plates, each plate having a reinforcing rib extending substantially throughout its length and substantially at right angles thereto.

6. An investment holder comprising a pair of flat spaced plates, each plate having a plurality of longitudinally extending re inforcing ribs.

7. An investment holder comprising a pair of spaced, flat plates, curved connecting portions between said plates, said portions being disposed in the same cylindrical surface and reinforcing ribs extending laterally from said plates and having their free` edges disposed in the said cylindrical surface.

8. An investment holder comprising a pair of spaced, flat plates, curved connecting portions between said plates, said portions being disposed in the same cylindrical surface, each plate having a reinforcing rib extending laterally from its outer face, the outer edges of the ribs being disposed in said cylindrical surface.

9. An investment holder comprising a pair of spaced, flat plates having reinforcing ribs extending laterally from the outer surfaces thereof.

10. An investment holder comprising a pair of spaced, fiat plates, each plate having zftreinforcing rib extending laterally thererom.

11. An investment holder comprising a izo pair of spaced, fiat plates, a flange extending laterally from one end of each plate, said flanges forming a flat surface and an annular collar extending beyond one end of thel holder and connected to said flanges.

lll. An investment holder comprising a pair of spaced parallel plates, means extending throughout the length of the plates and connecting the edges thereof, a flange at one end of each plate extending laterally therefrom, said flanges having curved outer edges and an annular collar extending beyond and secured to said flanges art the curved edges thereof.

15. An investment helder' comprising a pair of spaced parallel plates, means extending throughout the length of the plates and connecting the edges thereof, a flange at one end of each plate extending laterallyT therefrom, said fianges having curved outer edges, an annular colla-r extending beyond and secured to said fianges at the curved edges thereof and a laterally extending reinforcing rib secured to each plate.

16. An investment holder comprising a pair of spaced, parallel plates, curved means extending throughout the length of the plates and connecting the edges thereof, a

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flange at one end of each plate extending laterally therefrom, said flanges having curved outer edges and an annular collar eX- tending beyond and secured to said flanges at the curved edges thereof, and to the curved ends of the plate connecting means.

17. An investment holder comprising a pair of spaced, parallel, flat plates, connecting means between the longitudinal edges of said plates, said means having openings therein.

18. An investment holder comprising a pair of spaced, parallel, flat plates, connecting means between the longitudinal edges of said plates, the connecting means at one edge of the holder having an opening adjacent one end thereof and the other connecting means having an opening adjacent the other end thereof.

19. An investment holder comprising a pair of spaced, parallel, flat plates, connecting means between the longitudinal edges of said plates, said means having openings therein, each of said plates having a longitudinally extending reinforcing rib thereon.

ln Witness whereof, l have hereunto set my hand this 29 day of May, 1922.

MARTN F. BURNS. 

